Question

A person is suffering from myopia as well as hypermetropia. He needs lenses of power-5.5Dand +5.5D for correcting myopia and hypermetropia respectively. Find the focal length of the lenses use by him in spectacles to correct myopia and hypermetropia

Answer 1

Dear Student,

For the myopia, the focal length of the lens should be

$$\begin{gathered} -5.5=\frac{100}{f}\mathrm{cm} \\ f=-18.18\mathrm{cm} \end{gathered}$$

For the hypermetropia, the focal length of the lens should be
$$\begin{gathered} 5.5=\frac{100}{f}\mathrm{cm} \\ f=18.18\mathrm{cm} \end{gathered}$$

Regards